The Collaborative International Dictionary of English v.0.48:

Haslet \Has"let\ (h[a^]s"l[e^]t), n. [F. h[^a]telettes broil,
   for hastelettes, fr. F. haste spit; cf. L. hasta spear, and
   also OHG. harst gridiron.]
   The edible viscera, as the heart, liver, etc., of a beast,
   esp. of a hog. [Written also harslet.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

haslet
    n 1: heart and liver and other edible viscera especially of
         hogs; usually chopped and formed into a loaf and braised